Copper and process of producing the same.



W. M. PAGE & W. TASSIN.

COPPER AND PROCESS OF PRODUCING THE SAME.

APPLIOATION FILED APR.28, 1910. RENEWED JUNE 18, 1914.

1,125,164,. Patented Jan.19,1915.

5 SHEETS-SHEET 1.

3110c 1 1 fez-S W. M. PAGE &: W. TASSIN.

COPPER AND PROCESS OF PRODUCING THE SAME.

APPLICATION FILED APILZB, 1910. RENEWED JUNE 18, 1914.

Patented Jan. 19, 1915.

5 SHEETS-$113111 2.

Q-Qitm coma Patented Jan. 19, 1915.

5 SHEETS-SHEET 3.

Q QL 11400000 W. M. PAGE &. W. TASSIN.

COPPER AND PROCESS OF PRODUCING THE SAME.

APPLICATION FILED APR. 28. 1910. RENEWED JUNE 18.1914. 1

Patented Jan. 19, 1915.

' 5 SHBETSSHEET 4.

ZV/rZ Zkss/W wwmeooeo W. M. PAGE & W. TASSIN. COPPER AND PROCESS OFPRODUCING THE SAME. APPLICATION FILED APR. 28, 1910. RENEWED JUNE 18,1914.

1,125,164, Patented Jan.19, 1915.

5 SHEETS-SHEET F WILLIAM MARsnALn men, or PHILADELPHIA, ND .wm'r.rAs'sIN, or cnnsrnn, PENNSYLVANIA, ASSIGNOBS cro'rrm DUPLEX MET L-sCOMPANY, or. NEW YORK,

N. x, A coItPoaAmIoN or NEW YORK.

COPPER AND rnocEss or PRODUCING THE sAM Specification of Letters Yatent.

Patented Jan. 19, 1915.,

Application filed April 25, 1910, Serial no. 558,093. Renewed June 18,1914. Serial No. 845,976.

. per-clad metals and processes of producing the samefand it comprises anew form crystalline, fine textured copper, such copper beingsuhstantiallyfree ofogrygen and oiiids, carbon 'iron and exhibiting uponpolishing and etching a section of a casting a relatively coarse andflaky or platy macrostructure, free of visible lines of demarca tion" orcleavage between the component plates or flakes, such platesor flakesunder the microscope appearing integrally umted and each such plate: orflake showmgvery small isometric crystals regularly arranged and havingthe same lines of orientation in any one plate' though haying drtl'erentl nes in adjacent plates or'flakes; and 1t also comprises'"clad metalart cles proyi de d W1th a layer of copper hayingthe descrlhedproperties an 'a'ppeatancei and further comprises a Inetliodotproducmgsuch copper and of attaching such cop' er to other metals, saidmetho'dcomprising the steps of freeing copper of oxygen and oxids solution ormetallic iron or steel therein and a subsequent limited oxidation to reye the cxce'ss'o'f such iron where an e'xcess'is used;

all as more fully 'hereinaftersetforth as claimed. I

T e rd ary go ppe of h ma kets thou yery frequently nearly pure andcontaining hut'a limited'absolute impurities is Yery inu'ch afiected,as' j'to properties by .the limited amounts of such 1mpurities which doexist. contains both cuprous and cupr o oxids the forme'nbe ng P ly, aleast o a la ge e'x ent'ymtm form of a solid so utio'n. Cluprous oxid issoluble in molten copper audit probably does not separate to anyritent'iuso lidifica tion of. such copper." The 'cupricioXid on the otherhand'exlst's, least partially, in

a discrete form; as particles separate from the copper particles. Onmicroscopical. examination of a polished and etched surface, it shows amore or less granular structure with, usually, more or less cupric oxidbetween and bounding the grains and there are clearly evident lines ofdemarcation be-" tween such grains. There are also minute depressions orpitting. Ingot copper con.- tains oxygen and othergases; partly in theform of a solidified solution, probably, and partly also in theform ofbubbles or imprisoned bodies, causing the Well known sponginess of castcopper. There are also minute quantities of other metals; partlypresent, probably, as oxids and partly, probably, in the metallic form.All these impurities affect both of two of the important properties ofcopper; its strength and its conductivity. In so far as cupric oxid ispresent in the copper as such it'must of course form a weakeningconstituent $111.08 1t herever itis present-and since it is not a goodconductor it must also reduce the conductivity by lessening theconducting section Wherever it occurs. The cuprous oxid also reducesboth strength and conductivity and the 'sponginess likewise reduces bothprop.- erties. The dissolved gases and oxids and foreign metals alsoreduce the conductivity; and, probably, in most cases, the strengthalso. These contaminations ofcommercial ingot copper are dueto andaccuratelyrepresent the conditions under which the usual preparation,purification and castingv of copper are performed.

In the'ordinary operation, the copper is melted in some type of flameheated furnace, the flame being run oxidizing for the sake of a quickdevelopment of heat though the copper is melted and cast at'as low atem-.

- prerents metallic union of copper to copper ordinarily poled with awooden pole. WhlOll 1 n charring evolves reducing gases 7 which arepresumed to remove the absorbed oxygen and to reduce contained oxids,the poling operation being carried on till a removed sample shows thedesired fracture" and-texture; the ordinary texture of commerclal ingotcopper. The reducing action is never carried on to the limit or indeedvery far, overpoled copper not-being considered as good in quality asthat which has,

been poled to a less degree. The reason for this is not definitely knownalthough it is being in a succession of waves.

assumed that a continuation of the poling long enough to produceoverpoled copper results either in the reduction of the oxids of foreignand harmful metals or in a solution of carbon. Since the oxids of mostof the metals injurious to copper are as easily reduced as copper oxid,or even more easily, the former explanation has not gained fullcredence. Another explanation is that the presence of a certain amountof cuprous oxid in copper is desirable as giving the copper betterproperties. At all events in practice the poling is never continued longenough to remove all contained oxygen and oxids. After the poling, thecopper is cast into ingots. As stated, at the time of casting the moltencopper is usually rather low in temperature, not being ordinarily muchmore than hot enough to flow, and not so freely fluid as at highertemperatures. And from this low-temperature molten copper the oxids andother impurities do not rise freely by floatation; this beingparticularly the case with the black or cupric oxid which iscomparatively high in specific gravity. In casting the copper, furtheroxid is formed since hot copper in contact with air instantly becomescovered with a layer of oxid, so that in passing through the air, thesurface of the molten stream becomes oxidized. And as the molten copperis at a comparatively low temperature, the first portions entering themold chill enough to set quickly and retain the oxid in the mass asentangled skins and films. In a 4-inch wire bar ingot, for example, astudy of sections under the microscope will show that it may beconsidered, broadly speaking, as composed of three parts. In the bottomlayer, composed of the copper first entering into and splashing in themold, the copper may be regarded as All these waves, because of thechilling action of the mold, set almost immediately and the film coatingof oxid which they carry remains entangled and held in the solidifiedcopper. As the copper rises into the second third of the mold, thissplashing or Wave action ceases and the incoming stream of hotter meme-emolten metal forces its way downwardly through the top layer,.-al'lowing the oxid to rise to a certain extent and float at the top.This floating oxid is carried to the top of the mold and since the toplayer in the mold sets very rapidly on finishing the casting, the

. top layer of metal always carries muchentangled oxid. v

In the center of a bar of copper produced in the described manner thereis usually a limited portion of copper relatively free from oxid. In amicroscopic examination of polished and etched copper from such aningot, the surface appears-to be composed of small grains and betweenthese grains often occur black lines of copper oxid. In extending such abar to 'form wire, the oxid of copper separating the crystals formslines of weakness and of insulation, reducing both;

the strength and the conductivity. Obviously, wherever in the interiorof the mass copper oxid spaces copper" from copper, not only is thestrength locally reduced but the conductivity is locally lessened. Theexam ination of the copper either in the bar or in the wire, as stated,also shows pitting, 'due to the liberation of absorbed gas in thesolidificationpf the ingot. In good ingot copper the amount of thepitting and of the oxid is always small and, as stated, differentportions of the same ingot or of the wire drawn from the ingot will showquite different amounts of both, but both are usually found and in someparticularly bad specimens of ingot copper, the copper under themicroscope may be said to look like a conglomerate or concreteconsisting of a copper aggregate in a cupric oxid matrix.

In the present invention, molten copper I metal is maintained during theoperation at 1 a relatively higher temperature than is usual 1t beingfound that, contrary to the usual impression, under the hereinafterdescribed conditions, high temperature and a long-continued heating arenot detrimental. This is, very probably, because of the peculiarconditions. Copper at this high temperature is freely fluid, allowingnon-metal- 11c 1mpurities to rise easily and completely therethrough.Having the copper in this highly heated, freely fluid condition, andadvantageously the temperature may be above the melting point of steel,metallic iron or steel is added in such a manner as to distribute itthrough the mass. In the presence of this dissolved and disseminatediron, all the oxygen present, whether merely dissolved or in combinationwith the copper, at once combines-with the iron, forming oxids of iron,which risethrough the freely fluidv copper and float upon its surface.The

mamas amount of iron or steel used may 'be merely that required toremove the oxygen, or it.

may be in some excess, this excess being later removed by thehereinafter described method. The iron may be added as copper-clad steelscrap, or as ironor steel. The

iron or steel need not be clean and maybe contains ferrous oxid, areducing body.:

Such of the scale as does not take part in the reaction rises throughthe copper harmlessly. The carbon, silicon, manganese, etc., in the ironor steel also take part in the re ducingaction to an extent proportionalto their amount; the carbon forming gaseous oxids which produce anebullition and exercise a stirring action. Practically all the bodiespresent in steel, like iron, have a reducing action upon the oxids ofcopper and are able to remove dissolved oxygen. Ad-

vantageously, the treatment with the. iron orsteel-can be performed byrabbling, stirring or agitating with steel or iron bars, the moltencopper being in the form of a relatively deep bath. With copper at atemperature above the melting point of steel, the particles of molteniron tend to rise through it and produce an intimate mixture andthorough reduction. After this treatment, the copper is free of oxygenand oxids and of all foreign materials save for the presence of ironwhere an excess has been used. The iron oxid and other oxids produced inthe reaction rise to the surface of the fluid copper. It is nextnecessary to remove any excess of dissolved iron. For this purpose, the

cop er may be melted in a flame heated .furnace with the flame of thefurnace sweeping I close to its surface, such copper being kept coveredwith floating carbon, such as charcoal or coke, or both. With the flamesweeping close to the surface of the copper, the usual air layer betweenthe flame and the metal is practically absent and no opportunity isafforded for free oxidation. I In the presence-of the carbon floatingupon the copper, such oxygen as is present and the carbon dioxid of theflame both tend to form carbon monoxid. Practically under the describedconditions the surface of the popper is blanketed by a bath of carbonmonoxid and some carbon dioxid. Both these gases are oxidizing to iron,but are not oxidizing to copper. And while carbon monoxid is soluble inmolten copper under some conditions no material solution appears tooccur here. By treating the iron-containing copgen, oxids, ironand-dissolved gas and displaying new and advantageous characteristics.Suchcopper upon casting gives a homogeneous" ingot, showing nos'ponginess due to the development of gas in solidification, andshowingno lines of oxid when a cast specimen is polished and etched. It is,

furthermore, free of dissolved cuprous oxid.

Cast copper of this character when polished and etched in "fact shows anew and distinctive surface appearance. In lieu of showing a smallgrained'texture with clearly marked ,lines of demarcation between theseveral" grains, and frequently, lines of black oxid as well, it showsupon polishing and etching comparatively coarse or large plates orflakes plainly visible to the naked eye without noticeable lines ofdemarcation, of cleave age or of separation between adjacent flakes orplates. 'Each such flake in turn shows a microscopic substructurecomposed of orientated isometric crystals.v The lines of orientationinany one flake or plate are parallel and like in direction, while thelines in adjacent flakes or plates are not so parallel.

Any suitable type of furnace or melting apparatus may be used inperforming the described process, but some type of oscillating ortilting furnace may be advantage-' excess of iron. A tiltingfurnaceprovided with a deep well for the reception of molten copperduring the first stage and a large relatively shallow reverberatoryhearth for use during the second stage is particularly suitable. Thedeep well may form a lateral pocket at the side of a tilting furnace ofsubstantially cylindrical cross section.

The copper after the purification may be cast at once in any of theordinary forms of ingot mold. At thedescribed temperature it is .thinlyfluid and oxid formed during the pouring operation-rises in the copperin the mold and does not contaminate the body of the copper. If desired,however, the casting may be done under special circumstances precludingoxidation during the pouring, as when the copper is to be allowed tofall in temperature and cast at the usual comparatively low temperature.In such event, it may be cast directly into a mold filled with producergas or other inert gas. Or the mold may contain a body of hot moltenslag or flux. -The use of a mold containing a protective substance, suchas a gas or slag, may of course be resorted to when casting the copperat a high temperature. There is no reason with the present type ofcopper why casting should not be at a high temperature since a hightemperature per 'se is not injurious in the present operation.

the

The described type of copper is advantageously employed for forming themain body of the "coating of copper clad steel. For copper clad steel itis desirable that the coating be as impervious as possible and for mostpurposes that it have a high conductivity for heat and electricity. ForWire and sheets it is also desirable that the clad metal have a hightensile strength. The described type of copper being free of pits orsponginess, allows the production of comparatively thin films upon steelwithout risk of porosity which will permit corrosive agents to penetratethrough to the underlying metal while its conductivity and strength makeitvery suitable for thicker clad articles. Tn producing clad metals withthis type of copper, the production of the copper can be advantageouslycombined with that of the clad metal itself. For this purpose thenecessary treatment with iron may be given while treating a billet orother body of ferrous metal which is to be coated. For instance, a bodyof copper, (which may be fairly impure) may be treated by dippingtherein a billet of steel which is to be susequently coated. The steelin passing through the mass will afiord the necessary iron to reduce theoxids and combine with the oxygen present, and will also become coveredwith a thin, welded-on, cohering coating of copper which will remain onit when withdrawn. Such withdrawal is best into a neutral atmosphere,such as producer gas, to shield the hot clinging copper againstoxidation. Even with producer gas it is best to remove any containedoxygen or carbon dioxid, as by a previous treatment of the gas withsuitable chemicals such as an alkaline solution of pyrogallic acid.

Since the oxidation of carbon is preferential over the oxidation ofiron, in this dipping operation under the described conditions usingcopper containing oxygen the superficial carbon in the steel is burnt 0roxidized out, leaving a layer of carbonless iron with which the copperunites freely to form the described coating. Certain alloys are producedalso by the union of the iron and the copper, and the alloys producedunder these circumstances are materials of desirable properties, havinga good degree of tensile strength so that their presence is advantageousin the finished article. Genera'lly next the steel there is a layer ofalloy high in iron and low in copper while beyond it exteriorly is alayer of alloy rich in copper and low in iron.

In making the clad metal, and particularly where the copper is alreadyfairly pure, not containing much dissolved and combined oxygen, andwhere the steel contains considerable carbon, it is often advantageousto add some oxygen in the form of iron oxid to reinforce the oxidationof the mas er carbon. For this purpose, the billet may be preliminarilygiven a cleansing, as by sandblasting and pickling to remove coarsescale,

sand, etc. The billet which may have been part from the decarbonizedmetal beneath.

T he heat of molten copper is sufiiciently for this purpose. This pureiron is advantageous for the present purposes because it dissolves morefreely in copper than do the ferrous carbids found in steel, to producethe purifying iron in solution, and it forms the desirable linkingalloys and promotes the production of the weld-union. In thepurification of the copper, the ferrous oxid of the magnetic oxid playssome part; partly, probably, by reduction.

After the reaction is complete which is shown usually by the cessationof ebullition due to the evolution of carbon oxids, the billet may bewithdrawn, and is found covered as stated with a clinging coheringwelded-on coating of copper. Against this copper filmed surface may nowbe cast a further amount of copper to produce a coating of the desiredthickness. While copper may be attached to the filmed surface in othermanners, it is desirable that it be applied in the molten state and thatit be, for the purposes of the present invention, the purified copperpreviously described.

The bath of copper from. which. the billet has been withdrawn may nowcontain an excess of dissolved iron. In such event it is treated by anearly impinging flame in the presence of carbon in the manner describedto remove this excess of iron, the flame,

being so directed as to sweep close to the surface of the molten metal.The purified copper-may now be applied to a previously filmed billet inany convenient manner. Or, if the operation is properly conducted, theamount of iron dissolved from the billet may be merely that necessary toremove the oxids from the copper, leaving the copper substantially pureand ready for forming the coating. This correlation between the amountof iron dissolved and the amount of oxids in the copper may be easilyadusted by a little practice and experiment, so that the dipping of thebillet and the purification of the copper are simultaneous operations.In operating in this manner,

'. there is, strictly speaking, no excess'of iron dissolved in thecopper; there is merely the amount of iron dissolved which is requisitefor the purification of the copper bath.

In applying the purified copper to the filmed billet in the mannerdescribed it is advantageous to allowthe temperature of the copper todrop somewhat, this being for the reason that the very hot copper mightmelt ofi thecopper iron alloys on the surface of the billet and becomecontaminated. By a further adjustment of conditions in the operation.however, this reduction in temperature may also take placesimultaneously with the filming and the purification ofthe copper. Wherea small amount of very hot copper is contained in a comparatively smalldippin vessel and the relatively cooler billet ipped therein, the firstaction is that of heating the surface of the billet to a very hightemperature. temperature the solution of the iron, the reduction of theiron oxid, where such is present, and the purification of the copper allgo on at'once. As the heat penetrates inward in the billet, thetemperature of the surrounding copper drops until it reaches the desiredlower temperature, whereupon:

this copper may be directly applied ,to the filmed billet. For somepurposes, a convenient method of operation is to run very hot copperintoa relatively small hot dipping pocket or container, dip abilletthereinto until the copper is purified and the surface of thesteel covered with welded-on copper, and then follow by dropping aroundthe billet a mold casing adapted to inclose an annular layer of copperofthe correct thickness,-about the billet, thereafter removing v jbillet, casing and contained copper together.

For this purpose, the billet should be provided at itslower end with acap or disk adapted to make a tight joint with the easing, It is betterhowever to perform the operation in two sta'ges,first, alloy coating thebillet in the manner described and then bringing the copper into contactwith the alloyed surface.

copper asit'flows in to solidify first on such inner margin andultimately fill up the space between such solidified copper and thefilmed surface. Operating in this manner there is no danger of apermeation of the iron of the .iron-copper alloy on the billet throughthe whole mass of the coating. Where electrical conductors are to bemade this is very desirable for the reason that even a minimal amount ofiron runs down the conductivity of the copper inordinately. And with-thevery pure, highly conductive, special form of At this structure, thecopper when once brought to 1 In doing this it is con-' .venient anddesirable to use. a relatively cool copper of the present invention, itisof paratus being alternately used for dipping and for forming thesubstantial coat. Operating thus, the billets may-be dipped into thecopper until enough iron has dissolved therein to remove all impurities,the purified copper then freed of iron in the manner described, allowedto fall in temperature and then used for forming coatings.

While ordinary, ladles or molds may be used in' connection with ordinarycopper melting furnaces in performing the described operations, asstated, it is better to use a rocking furnace with a built-on dippingdevice adapted to allow a to-and-fro flow of molten copper as this givesa better control of conditions and minimizes the chance of contaminationof the molten copper during the operation. With such a the describedcondition may be kept of the proper composition; and it has the furtheradvantage that by proper correlation of relative dimensions andconditions, the described unitary operation of alloying'the billet,purifying the copper and reducingits temperature may easily be carriedon. The molten copper from the furnace may, for example, be flowed intothe dipping device' at a temperature of, say 1380 (l, which adapts itboth for alloying the billet and for purification by iron dissolved offthe same, and then by the chillingaction of the billet it may be reducedto, say, 1280L- After the coating operation, the residual copper may berun back" into the furnace and brought back to a high temperature. Witha proper correlation between the dimensions of the billet and the amountof copper in the dipping bath, it is easily practicable tobring about atemperature drop of a hundred degrees in the operation itself.

In lieu of using ordinaryiron or steel as the core metal of course anyof the commercial alloy steels or ferro metals, such 'as '115' chropiesteel, manganese steel, nickel steel, coba t steel, etc., may beemployed. Or, 'one of the iron-like metals, such as nickel or cobalt maybe employed in lieu of steel or-iron.

ln the accompanying illustration are shownmore or less diagrammatically,certain apparatus useful in the described process, and there are givencertain v ews representing the metal, these views belng taken from oninal photomicrographs filed herewith, said views representing saidphotomr. crographs as nearly as may be withln the limits by the PatentOffice requirements for v patent drawings.

' In this showing: Figures 1, 2, 3 and 4 i Ml tion to inch rod; Fig. 11shows a micro? show views on an enlarged scale of polished and etchedmasses of ordinary copper of different brands; Fig. 5 shows a similarsec-- tion of anordinary commercial wire bar; Fig. 6 shows a simliarsection of copper which has been twelve hours molten in a crucible;Figs. 7, 8 and9 are representations of the microscopic appearance of thenew copper and Fig. is a similar view of the same copper after havingundergone reducscopic view of the structure of steel and In theapparatus of Figs. 12 to 15, 1 rep-.

resents a metallic casing of any suitable material lined. withrefractory material 2 and having a central flame chamber 3.Comvalvedpipes 15 and 16 feeding burner 1T municating with this chamberare ducts 41 set at an angle and communicating with chamber 5 for moltenmetal. This furnace chamber is arranged to be tilted on a horizontalaxis and to facilitate tilting it is provided with bearings 6, and ashoulder 7 provided with lever arm 8 carrying a weight receiving device9 to aid in counterbalanc ing. At one side opposite the metal duct thefurnace chamber is shown provided with port 10 adapted to be closed byswinging door 11. 12 and 13 represent the framework carrying thefurnace. Oil pipes 14 (see Fig. 1 1) provides for firing at either orboth ends of the flame chamber by means of provided with air or steaminjecting means 18. When the apparatus is to be used for coating iron orsteel with the new copper, a dipping casing 19 provided with means 20for introducing. producer gas or other inert atmosphere and hoistingmeans 21 and 23 may be employed. This casing surrounds billet 22 whichmay have been sandblasted or otherwise treated and is provided with anend cap 2% adapted to make a tight joint with the bottom of the casingand an inlet 25 provided with sealing means 26. This sealing means maybe a ring of asbestos or metal which is adapted. to be ushed aside whenthe orifice is to be used 'or the introduction of metal. When theapparatus is to be used for mak- \ng ingots of the new copper it may beprovided with a pouring lip 27 and suit able ngot molds 28. These in ctmolds may, if desired, be provided wit a filling me ian 29 of suitablefluxor slag adapted to be or become molten at the temperature of thecast copper, such as borax, cryolite, silicate of soda, iron slags, ahalogen compound, such as salt, etc., or an indifferent atmosphere, suchas producer gas, may be blown into the mold from pipe 30 during thepouring operation. This roducer gas will displace the air in the moldand prevent oxidation of the cast copper as it flows in the top of themold. It will burn in contact with the air but this burning is notinjurious to the operation. Ram 31 may be used in loweringand raisingthe chamber 5.

Tn'the showing of Fig. 1, the metal is an excellent quality ofcommercial copper, showing but little diflferentiation in texture.

In the showing of Fig. 2, which-is an ordinary grade of commercialcopper, the large white areas are grains of copper while the black linesrepresent layers of oxid therebetween. The showing of Fig. 3 is aboutthe same. As will be observed, both samples are rather bad.

In the showing of 'Fig. 4c, the white and dark areas both representcopper while the black spots are pittings and oxids. And by carefulexamination it will be noticed that there are lines of separation anddemarkation between the crystals of copper and these lines contain moreor less oxid of copper.

Fig. 5 represents the microstructure of a sample of ordinary wire bar.

Fig. 6 is copper which has been molten in a crucible for 12 hours buthas not been purified and shows a crystallization of copper togetherwith impurities and pitting. It shows one dendritic crystal of copper.

Figs. 7, 8 and 9 show as nearly as possible within the limits ofphotography, the peculiar optical appearance under the microscope of asection of the new copper. After the new copper is well polished and isetched somewhat it displays to the eye a peculiar flashing appearance asif the sur face were composed of lakes or plates without -visible linesofdcniarkation between them. This optical appearance while verycharacteristicand.veryfldistinctive is hard to reproduce. views, thisstructure is less evident but the On enlargement as in these sets ofparallel crystals together form the flake-like areas visible to thenaked eye. Tn these views the flakes are resolved into microstructure ofparallel isometric crystals regularly arranged. Figs. 8 and 9 show thisparallelism very clearly. Fig. 10 shows a microview of the same copperwhich has been drawn out to inch rod. Tn drawing out the copper, thepeculiar structure of the ingot copper is of course changedconsiderably. Fig. 11 shows a view on the same scale of a clad metalbillet, the view being taken across the line of joinder. The upper.troduced.

back into the-purifying position and intro ducing a layer of floatingcarbon upon the or homogeneous looking area is the copper and .the.lower. is the steel. Inpolishing a sample suchas this, it is difiicultto adopt a method of polishing and etching which will show the peculiarmicrostructure of both metals. Between the upper copper area and thelower 'steel area is'shown a band or layer of copperiron'alloys. thisband will'be seen to have an upper blackish area which is a high copperalloy. Below this are grayish areas of various copper iron alloys andbelow these again there is a layer of high iron alloy. The copperextends more or less into the edge of the iron area.

In the apparatus shown the copper .may

be melted in the chamber 3 by the oil flames from 17 The furnace may nowbe tilted and iron introduced in the copper in chamber 5 best by dippinga billet-or ro'd therein. The

copper for this operation is best ata temperature above the meltingpoint of steel. T he steel melting and dissolving in the copper frees itefiectually of oxygen and oxids, while by dipping the relatively lightersteel in the relatively heavier copper the molten particles of steelupon rising flow through thecopper and give a good distribution of irontherein.- By carefully controlling the conditions of the operation,merely the amount of steel may .be introduced which sufiices to removeoxygen and oxids, leaving the copper ure. I Ordinarly an excess is inponnow tilting the furnace surface of the copper, upon heating with the oilflame, this excess of iron burns out,

leaving copperof the composition described. Upon again tilting thefurnace the purified copper flows out into chamber 5- when it may beeast through 27, into the ingot mold 28. Or the billet 22 may. be dippedin the chamber 5, at once serving to purify the brought to a very hightemperature in 3,-

transferred into 5 and the relatively colder billet introduced. Theconduction of heat through steel being relatively .slow the surface ofthe billet acquires the temperature of the copper, suflicient irondissolves to remove oxygen and oxids, forming floating oxid of iron, andthen thetemperature of the purified copper is somewhat reduced. Upon nowintroducing the billet into the casing in such manner that 24 makes aseal Upon examination at the base of the casing and dropping ca sing andbillet together into chamber .5, .the

copper is now cooled down to a castingtemperature and it may be allowedto flow. in through 25, 26-being removed, toform the main body of thecoating.

What we claim is:.--

1. The process of purifying copper which comprises treating suchcopperin .a highly heated molten condition with iron in excess of theamount suflicient to react with oxygen and oxids present and thereafterremoving such excess of iron.

2. The process of purifying copper which comprises treating such copper1n a highly heated molten condition. with iron in excess of the amountsufficient to-react with oxygen and oxids present and thereafter burningout such excess of iron under conditions precluding re-oxidation of thecopper.

3. The process of purifying copper which comprises treating such copperin a highly such excess and then producing a solidified body of copperunder conditions precluding reabsorption of oxygen.

The process of preparing copper castings which comprises treatingcopper. in a highly heated molten condition with iron in excess of theamount suflicient to react with oxygen and oxids present, removing suchexcess and'the n producing a solidified body of the copper in anatmosphere of inert gas.

6. The process of purifying copper which comprises treating highlyheated -molten copper by contacting the same with a body of steel untilsufficient iron has dissolved to remove oxygen and oxids, removing thebody of steel and heating the copper under conditions. permitting apreferential oxidation of the dissolved iron until such iron is.removed.

7.. The process of purifying copper which 8. The process of purifyingcopper which comprises bringing copper to a highly heated. moltencondition in a tilting furnace provided with a dipping pocket, tiltingthe furnace to flow the coppermto such pocket,

rte

8 Y mama i dipping a steel object into the copper until sufficient irondissolves to free the copper of oxygen and oxids, returning the copperto the furnace and burning out the dissolved iron.

9. The process of purifying copper which comprises bringing a body ofsuch copper to a temperature in excess of that required to melt steel,dipping in a body of steel until sufiicient iron has dissolved to removeoxy gen and oxids, burning out the excess of iron by preferentialoxidation and forming a solidified body of the purified copper.

10. In the purification of copper, the process which comprises stirringmolten copper with a steel object until oxygen and oxids are removed,burning out the excess of dissolved iron by preferential oxidation andforming a solidified body of the treated copper under conditionsprecluding oxidation.

11. In the purification of copper, the process which comprises stirringmolten copper at a temperature above the melting point of steel with asteel object until oxygen and oxids are removed, burning out the excessof dissolved iron by preferential oxidation and forming a solidifiedbody of the treated copper under conditions precluding oxidation.

12. In the purification of copper, the process which comprises stirringmolten copper with an oxidized steel object until oxygen and oxids areremoved, burning out the excess of dissolved iron by preferentialoxidation and forming a solidified body of the treated copper underconditions precluding oxidation.

13. In the purification of copper, the process which comprises stirringmolten copper at a tempertaure above the melting point of steel with anoxidized steel object until oxygen and oxids are removed, burning outthe excess of dissolved iron by preferential oxidation and forming asolidified body of the treated copper under conditions precludingoxidation.

14. As a new article of manufacture, an object comprising a body ofcopper substan tially free of oxygen, oxids and iron, said body uponpolishing and etching exhibiting a relatively coarse platy or flakymicrostructure and microscopically examined displaying a crystalstructure of regularly arranged isometric crystals having the sameorientation within any one flake or plate, the lines of orientationwithin adjacent flakes or -plates not being the same, but displaying noapparent line of cleavage or demarkation between such adjacent flakes orplates.

15. The process of" purifying copper, which comprises bringing copper toa highly heated molten condition, forming a relatively deep dipping bodyof said molten copper, dipping a steel object into the body of moltencopper thus formed until suliicient iron dissolves to free the copper ofoxygen and oxids, and then forming a relatively shallow body of saidmolten copper and burning out the dissolved iron.

16. The process of purifying copper which comprises bringing copper to ahighly heated molten condition, forming a dipping body of said moltencopper of considerable depth but relatively smallhorizontal crosssection, dipping a steel object into the body of molten copper thusformed until suflicient iron dissolves to free the copper of oxygen andoxids, then forming a relatively shallow body of such molten copper, andburning out the dissolved iron therefrom.

In testimony whereof, we aflix our signatures in the presence ofwitnesses.

WILLIAM MARSHALL PAGE. A IVIRI 'IASSIN. IVitnesses I M. Wars,

JOHN B. PA'r'roN.

